Manufacture of wrought iron



Patented 15, 1935 MANUFACTURE OF wnoUGIrr moN James Aston, Pittsburgh,and Edward 3; Story, Dormont, -Pa., assignorsto A. M. Byers Com pany,Pittsburgh, Pa.,

. sylvania a corporation of Penn-- No DrawingApplication,January2411934,

Serial No. 703,140 J 7 Claims. (01. 75417 This invention relates to themanufacture of wrought iron, and more particularly to the manufacture ofwrought iron by the Aston process. It relates still more particularly tocertain im- 5 proved methods of manufacturing Aston process wroughtiron, and especially balls weighing in the neighborhood of threethousand pounds and upwards. The invention has to do primarily with therelationship between the amount of ferrous material and the amount ofmolten slag admixed in the formation of larger sized balls of wroughtiron by the Aston process.

This application is in part a continuation of our copending applicationSerial No. 626,988, filed July 30, 1932.

The Aston process of manufacturing wrought iron is now well known andcomprises admixing ferrous material and molten slag, preferably bypouring molten ferrous material into a slag bath in a receptacle, sothat the solidified or partly solidified granules of ferrous materialformed during the admixture are individually coated with slag and weldedtogether to form at the bottom of the receptacle a compressible mass orball of wrought iron. The ball thus formed can be compressed to form abloom which may then be rolled or reduced to a billet or any otherdesired form.

In the early experimental work on the Aston process relatively smallballs were formed. These balls ranged up to 2400 or 2500 pounds inweight or slightly over, but were very much smaller than the ballsordinarily produced in present day commercial operations. In themanufacture of the smaller experimental balls it was found that goodresults could be obtained with slag to ferrous material volume ratios ofin the neighborhood of 5, 6 or 8 to 1, that is to say, that up to about8 volumes of slag would be used for admixture with one volume of ferrousmaterial.

Although it might seem logical that the same slag to ferrous materialvolume ratios as were suitable for the formation of the smaller ballswould also be suitable for the formation of larger balls, we have foundthat, particularly in the formation of balls weighing in theneighborhood of three to four thousand pounds and upwards, this is nolonger true. Results obtained in attempting to produce balls of thissize using a slag to ferrous material volume ratio of about 8 to 1 orless are distinctly unsatisfactory. The ferrous material is improperlydisintegrated or shotted, there being metal in the region of the centerof the ball in a somewhat incipient state of fusion. When such a ball iscompressed it may behave badly; the surface may bulge due to :thetendency. of the half fused ferrous material at the center to exudetoward the surface. When the partly pressed ball is turned in the pressfor compression in another direction the bulge may again appear. 5Rolling in a blooming mill of a bloom thus formed may be extremelydiflioult, for again a pronounced bulging effect may be felt where thepartially fused ferrous material passes through the rolls. In a laterpass the bulging, tending to manifest itself 10 in another direction,may throw a fin or fold into the metal. Aside from the operatingdifficulties, the partly fused ferrous material results in wrought ironof inferior quality, being non-uniform and having undesirable propertiessuch as low tensile strength and ductility.

We have found that in the manufacture of balls weighing in theneighborhood of three or four thousand pounds and upwards a slag toferrous material volume ratio greater than 8 to 1 should be maintainedin order to avoid the disadvantages above mentioned. This is contrary tothe early experimental experience with balls ranging up to in theneighborhood of 2500 pounds, and the importance of a relatively highratio is especially pronounced in making balls over about four thousandpounds in weight. The broad range of slag to ferrous material ratioswhich we deem suitable for the larger sized balls is from 8 to 1 as alow limit to 25 to 1 as a high limit, and the preferred operating range,particularly in the formation of the usual commercial balls of fromabout three or four thousand to about ten thousand pounds, is from inthe neighborhood of 12 to 1 to in the neighborhood of 20 to 1. In somecases a higher ratio than absolutely necessary is utilized so that theremay be a factor of safety insuring complete disintegration of theferrous material. However, a ratio of greater than 8 to 1 in practicallyall cases and at least 9 to 1 or slightly greater in most cases is foundnecessary in making the larger sized balls and does not include anysubstantial factor of safety.

While we have described certain present preferred embodiments of theinvention, it is to be distinctly understood that the same is notlimited thereto, but may be otherwise variously embodied and practicedwithin the scope of the following claims.

We claim:

1. In the manufacture of wrought iron by the Aston process, the step, inthe formation of wrought iron balls weighing in the neighborhood ofthree thousand pounds and upwards, comprisingwfdmix'ifi' g' ferrousmaterial with more than eight times its volume of molten slag.

2. In the manufacture of wrought iron by the Aston process, the step, inthe formation of wrought iron balls weighing in the neighborhood ofthree thousand pounds and upwards, comprising, admixing ferrous materialwithbetween eight andtwenty -five' tiines its volume of molten slag.

3. In the manufacture of wrought iron by the Aston process, the step, inH the formation of wrought iron balls weighing in tlie rie'ig'hborhoodof three thousand pounds and'upwardacomprising admixing ferrousmaterial-wi thatleast about twelve times its volume of; molten slag:

4. In the manufacture of wrought iron by the Aston process, the step, inthe formation of wrought iron balls weighing iiithe neigliborll'ood ofthree thousand pounds and upwards, comprising admixing ferrous materialwith"between.

about twelve and about twenty times its volume rous material having avolume less than oneeighth the 'volume' of the slag.

7 A-method-ofmaking by the Aston process wrought ironballs: Weighing inthe neighborhood of foun thousa'ndmounds and upwards, comprisingintroducing -into a bath of molten slag ferrous materialhaving a volumenot over about ione=t1we1ftli the volume of the slag.

JAlWES ASTON. EDWARD B. STORY.

